Electric insulator.



a. w.. GHAPFIN. ELECTRIC INSULATOR.

' Patented July 18,1911.

sulators;

UNITED sTATEsrATENT OFFICE.

.GEORGE-W. CHAFFIN, Q]? DAYTON, OHIO.

nnnozrnicmsUnAroR.

I Specification of Letters Patent. Patented J 1 8, 1911,

application filed February 13, 1911. Serial No. 608,191.--

To all whom it concern:

Be it known thatl, GEORGE Crmrrm,

a citizen'of the United States, residing at Dayton, in the county of Montgomery and State of Ohio, have invented certain new and useful Improvements in Electric Inand I do declare the" followingto be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the acconipanyingdrawings, and to the letters and figures of reference marked thereon, which form a part of this specification.

This invention relates to improvements in electric insulators of the kind used for stringing wires.

More specifically speaking the invention .relatesto the pin or support upon which the glass insulator is mounted. The said pin or sup ort being of metal, of cast iron for examp e, and the insulator being of glass or similar material, it is important that the metallic-pin or support shall have the quality of contractin as well as expanding under the different egrees of temperature in order that the glass insulator may be properly protected from breakage due to such changes in temperature.

' It is the object, therefore, of this inven tion to so construct the pin or support that the same may have the necessary quality of expansion or contraction, and at the same time the structure of the metallic pin or support is not weakened to any extent that might impair its durability.-

The accompanying drawings clearly illustrate my said improvements, and these will now be referred to and. then a detailed description of said improvements will be given.

Figure 1 is a longitudinal vertical section of an insulator supported upon a pin constructed in accordance with my invention. Fig. 2 is a sectional view on the line a-a of Fig. 1. Fig. 3 is a longitudinal elevation of the-cast iron plug or insulator support removed from the insulator. Fig. 11s a View looking down upon the upper end of said pin, as shown iirl ig. 3. Fig. 5 is a perspective view of a sheet of felt or similar soft substance which is used between the body of the metallic pin and the glass insulator to protect the latter.

In a detailed description of the inven- 'or contraction for substantiall corresponding parts.

The metallic pin 1 is, as before stated, constructed of cast iron, a portion of the body of which is provided with annular screw threads whichengage similar screw threads of the glass insulator 2,'and the two thus become united. The end of the. pin 1 projecting from the insulator, is driven intothe cross arm or other support (not shown). The manner of attaching the insulator suption, similar reference characters indicate ports is so well understood as to make it unnecessary to illustratethe cross arm or any other support to which the pin may be attached. The screw-threaded portion of the pin is cut, as at 3 from a point near the base of the pin through to the end of said pin on one side with a solid portion or the end of the pin left intact, as at 4. The metal thus removed in producing the cut 3, imparts to the portion of the in inclosed bytheinsulator, the quality 0 expansion the length of that portion of the pin w i'ch engages the insulator. intact at one-corner of the screw-threaded end affords asuflicient sup ort for the sides of the pin thus separate portion to prevent any possible breakage of the pin owing to unusual pressure being exerted thereon. At the same time the portion of the pin supporting the glass insulator will have the necessary expanding and contracting quality to properly su port the glass insulator and afi'ord a sudcient protection. A sheet of felt 5 or similar material is passed through the opening 3 in the pin before said pin is inserted in the glass insulator. \Vhen the felt is thus passed through said opening, edges thereof extend beyond the sides of the )in, and when said pin is screwed into the insulator these edges lie between the glass insulator and the metal pin, as shown at 6 in Fig. 2, and thus provide cushions which'protect the glass from direct contact with the pin.

Having described my invention, I claim:

1. A metallic supporting pin for insulators having a screw-threaded body portion provided with-ea longitudinal opening extending through the end thereof, the said opening bein inclosed oh one s'de at the end of the pin liy a solid portion, w ereby the efiects of expansion are avoided and thedesired strength of the pin is maintained, substantially as described.

by the cut-out 2. A metallic screw-threaded supporting by the brid pin for insulators'having a longitudinal specified.- opening 3 extending through the screw.-

portion 4, substantially as 10 In testimony whereof Iaflix my signzitbteaded portion of said pin, said opening ture, in presence of two witnesses.

5 bein partially inclosed at the end of the pin-. yen integral portion 4, whereby elas- GEORGE OHAFFIN.

ticity and strength are combined, in said Witnesses: Hand a piece of yielding material lying. i R. J. MCCARTY,

opening and maintained therein HOWARD S. SMITH. 

